Scala 中的显式类型转换
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Explicit Type Conversion in Scala
提问by Kevin Albrecht
Lets say I have the following code:
假设我有以下代码：
abstract class Animal
case class Dog(name:String) extends Animal
var foo:Animal = Dog("rover")
var bar:Dog = foo //ERROR!
How do I fix the last line of this code? Basically, I just want to do what, in a C-like language would be done:
如何修复此代码的最后一行？基本上，我只想做些什么，用类 C 语言就可以做到：
var bar:Dog = (Dog) foo
回答by Kevin Albrecht
I figured this out myself. There are two solutions:
这是我自己想出来的。有两种解决方案：
1) Do the explicit cast:
1) 进行显式转换：
var bar:Dog = foo.asInstanceOf[Dog]
2) Use pattern matching to cast it for you, this also catches errors:
2）使用模式匹配来为你投射，这也会捕获错误：
var bar:Dog = foo match {
case x:Dog => x
case _ => {
// Error handling code here
}
}
